Key idea Matrix equations can be rearranged like algebraic equations, as long as operations are defined. Example: A2−5A+4I−X=0⇒X=A2−5A+4IA^2-5A+4I-X=0\quad\Rightarrow\quad X=A^2-5A+4IA2−5A+4I−X=0⇒X=A2−5A+4I